4. Soil Horizon
• A layer of soil that has identifiable
characteristics produced by chemical
weathering and other soil-forming processes
5. Soil Profile
• A vertical section through a soil showing its
succession of horizons and the underlying
parent material.
6. Pedalfer
• Soil of humid regions characterized by the
accumulation of iron oxides and aluminum-
rich clays in the B horizons.
7. pedocal
• Soil associated with drier regions and
characterized by an accumulation of calcium
carbonate in the upper horizons
8. laterite
• A red, highly leached soil type found in the
tropics that is rich in oxides of iron and
aluminum.
9. Key Concept
• Soil is the part of the regolith that supports
the growth of plants
10. Key Concept
• Soil has four major components: mineral
matter, or broken-down rock; organic
matter, or humus, which is the decayed
remains of organisms; water; and air.
11. Key Concept
• The most important factors in soil formation
are parent material, time, climate, and slope.
12. Key Concept
• Soil varies in
composition, texture, structure, and color at
different depths.
13. Key Concept
• Three common types of soil are
pedalfer, pedocal, and laterite.
14. Key Concept
• However, human activities that remove
natural vegetation, such as
farming, logging, and construction, have
greatly accelerated erosion.
